Random laser radiation behavior of liquid crystal in photonic crystal fiber carrier

A hollow-core photonic-crystal fiber filled with a mixture of nematic liquid crystal TEB30A, chiral agent S-811 and laser dye PM597 was pumped by a frequency-doubled Nd:YAG laser with a wavelength of 532 nm. The laser emission spectra was measured and the random laser radiation behavior in the photonic-crystal fiber carrier was investigated. When side-pumping was applied to the fiber, the emitted random laser with a wider radiation direction from the side face had a wavelength range of 590−605 nm and an FWMH of 0.3 nm. When end-pumping was employed to the fiber, the emitted random laser from the end face had a wavelength range of 580−605 nm and an FWMH of 0.3 nm. After the sample was heated to the isotropic temperature, the laser emission with both pumping methods was shut down. The experimental results demonstrate that the dye doped liquid crystal mixture in the micropore induce the random laser emission in the photonic-crystal. The change in the mean free path of photon transport and the fluctuation of the dielectric tensor of chiral nematic liquid crystals with temperature are the main factors affecting the laser intensity.